Electronic musical instrument with key-dependent time-variable delaying device

ABSTRACT

An electronic musical instrument includes in a tone signal path a signal delaying device constituted by a bucket brigade device to which is supplied transfer clock pulses which determine of the delay time. A keyboard is provided with a control voltage generator generating a control voltage representing the depressed key or keys. The control voltage is supplied to the clock pulse generator for determining the frequency of the transfer clock pulses generated thereby.

United States Patent 1191 Adachi ELECTRONIC MUSICAL INSTRUMENT WITH KEY-DEPENDENT TIME-VARIABLE DELAYING DEVICE [75] Inventor: Takeshi Adachi, Hamamatsu, Japan [73] Assignee: Nippon Gakki Seizo Kabushiki Kaisha, Hamamatsu-shi, Shizuoka-ken, Japan [22] Filed: Sept. 17, 1973 [21] Appl. No.: 397,748

30 Foreign Application Priority Data [58] Field of Search 84/l.24, 1.25, 1.04, 1.01, 84/1.l7; 179/1 J [111 3,835,237 [4 1 Sept. 10, 1974 [5 6] References Cited UNITED STATES PATENTS 3,288,909 11/1966 Volodin 84/1.25 X 3,626,078 12/1971 Sekiguchi 8471.25 X 3,749,837 7/1973 Doughty 179/1 J Primary Examiner-Richard B. Wilkinson Assistant Examiner-U. Weldon Attorney, Agent, or Firm-Flynn & Frishauf, P.C.

[5 7] ABSTRACT An electronic musical instrument includes in a tone signal path a signal delaying device constituted by a bucket brigade device to which is supplied transfer clock pulses which determine of the delay time. A keyboard is provided with a control voltage generator generating a, control voltage representing the depressed key or keys. The control voltage is supplied to the clock pulse generator for determining the fre quency of the transfer clock pulses generated thereby.

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, T 15a H g I30 Ef'TuiL 38m I 0 v0 GENS GEN. F I 3 P 14b 15b {ah I LOWER TONE w- KEY- OOLOR|NGBBO AMP- 1 BOARD CIRCUIT OONTROL- x VOLTAGE VCO GEN.

:flB-Zb F l G. 4 M 1snb 2m I ELECTRONIC MUSICAL INSTRUMENT WITH BACKGROUND OF THE INVENTION This invention relates to an electronic musical instrument including a signal delaying device whose delay time is variable dependent on which of the keys are depressed.

Where a performance is to be made on an electronic musical instrument with various effects such as vibrato and tremolo, the customary practice is to carry out the amplitude or frequency modulation of generator tone signals obtained upon key depression. Provision of such effects for musical tones is attained by actuating a modulation circuit through operation of specified switches. Accordingly, only a particular performance effect is always applied, regardless of the kind of tone signals generated or the manner in which a perfonnance isdisplayed. Namely, the same type of modulation is only obtained, whether low or high compasskeys are depressed, simply attaining a monotonous performance. Therefore, even when a vibrato or tremolo modification is imparted to musical tones, it has been impossible to realize a substantially full performance effect.

It is accordingly an object of this invention to provide an electronic musical instrument operable with a signal delaying effect, the delaying time being variable dependent on which of the keys are depressed, thus attaining closer truthfulness to natural musical instruments.

Another object of the invention is to provide an electronic musical instrument provided with upper and lower keyboard devices which can produce a versatile performance by causing tones resulting from depression of some keys on one of the keyboard devices to have different phases from the tones obtained by depression of the corresponding keys on the other keyboard device.

SUMMARY oF THE INVENTION According to an aspect of this invention, there is provided an electronic musical instrument operable with a signal delaying effect of a delaying time variable dependent on which of the keys are depressed, which instrument comprises tone generators producing tone signals; a keyboard device for selectively delivering the tone signals corresponding to the depressed keys; a signal delaying device supplied with musical tone signals derived from the tone signals and designed to have its delaying time determined by transfer clock pulses which are fed thereto; a transfer clock pulse generator of a voltage controlled type; and a control voltage generator associated with the keyboard and generating a control voltage representing which of the keys are depressed, the clock pulse frequency being determined by the control voltage.

According to another aspect of this invention, there is provided an electronic musical instrument producing musical tones by the corresponding keys on the upper and lower keyboard devices by varying the phases of said musical tones according to which of the keys are depressed, which comprises tone generators producing tone signals; upper and lower keyboard devices for selectively delivering tone signals corresponding to the depressed keys; a signal delaying device provided in at least one of a plurality of tone signal paths through which to conduct musical tone signals derived from the tone signals obtained by key depression on the upper and lower keyboard devices and designed to have'its delaying time determined by transfer clock pulses which are fed thereto; a transfer clock pulse generator of a voltage controlled type; and a control voltage generator associated with the keyboard and generating a control voltage representing which of the keys are depressed, the clock pulse frequency being determined by the control voltage.

BRIEF DESCRIPTION OF THE DRAWINGS erator of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A charge coupled device (CCD) usable as a signal delay line in this invention is a kind of bucket brigade device and is a novel semiconductor device disclosed by Mr. W. S. Boyle of Bell Telephone Laboratory (BTL) at the International Solid State Circuit Conference (ISSCC) in 1970, which device permits charges to move freely in two dimensional space and has a memory function. This conference was referred to in Silicon Technology Simplifies Devices, Electronics, Mar. 30, 1973, pages 45-48.

Referring to FIG. 1 a plurality of tone signals are selectively delivered from tone signal generators 11 upon key depression on the keyboard device 12. The tone signals thus produced are conducted to a tone coloring circuit 13 consisting of various tone coloring filters so as to be formed into musical tone signals bearing proper tone colors. Later, the musical tone signals are supplied to a signal delaying device 14, for example, made of a bucket brigade device (hereinafter abbreviated as BBD) having its delaying time determined by the frequency of the later described transfer clock pulses received. Output musical tone signals from the BBD 14 are transmitted to a tone-producing means having an amplifier l5 and a loud-speaker 16 so as to be given forth as part of a performance. The delaying device 14 may consist of a charge coupled device (CCD) as the BBD. For convenience, description is given of the BBD. As is well known, these types of delaying device are so designed as to cause an input signal to be conducted through consecutively arranged transfer electrodes, each time a control pulse cycle is re ceived. For example, where the delaying device consisting of 200 transfer electrodes is actuated by twophase transfer clock pulses having a frequency of 50 kHz, then an input signal will be delivered as an output signal with a time delay of 2 milliseconds by being carried through all said 200 transfer electrodes. In this case, transfer clock pulses of kHz gives rise to a 5 time delay of 1 millisecond and those of 30 kHz a time delay of 3 milliseconds.

The transfer clock pulses are delivered in two-phase from a transfer clock pulse generator 17 of a voltage controlled type (hereinafter abbreviated as VCO). The VCO 17 has its output pulse varied in frequency by means of the control voltage from a control voltage generator 18, which delivers a control voltage determined by which of the keys is now depressed on the keyboard device 12. The VCO 17 may comprise an astable multivibrator emitting a pulse signal whose frequency ranges, for example, between 100 and 40 kHz. Where a pulse signal of 100 to 40 kHz is applied to the 200 transfer electrodes of the BBD 14 in the two-phase form, then a time delay of l to 2.5 milliseconds is ob tained. Namely, the control voltage generator 18 should advisably be designed to generate such a control voltage as to cause thefrequency of the transfer clock pulses from the VCO 17 to be varied within the range of 100 to 40 kHz.

Referring to FIG. 2, tone signals representing a compass of, for example, C2 (65 Hz) to C6 (1,047 Hz) are conducted to the tone coloring circuit 13 through key switches 12-1 to l2-n operated jointly with key depres-' sion on the keyboard device 12. The key switches 12-1 to 12-n are made to work together with the auxiliary I switches 18-1 to l8-n of the control voltage generator 18. The auxiliary switches 18-1 to 18-n are connected at one-end to the corresponding taps of a potentiometer disposed between a DC. source of +V volts and ground, and at the other end to the input terminal of another VCO 22, the output terminal of which is connected to the input terminal of the first-mentioned VCO 17. Thus the switch 2l is impressed with a DC. voltage having a'magnitude decided by which of the keys are depressed. For example, where a key denoting C6 is depressed, then the key switch 12-1 and auxiliary switch 18-1 are closed to provide the highest level of voltage. Where a key of C2 is depressed, then the key switch l2-n and auxiliary switch 18-n are closed to generate the lowest level of voltage. Where a DC voltage I is supplied to the VCO 17 from any of the auxiliary switches 18-1 to l8-n through the switch 21, then the VCO 17 generates transfer clock pulses of kHz when impressed with voltage through the switch 18-ri, and a control pulse signal of 100 kHz when impressed with voltage through the switch 18-1. This arrangement enables the BBD 14 to produce musical tone signals with a time delay progressively decreasing from 2.5 milliseconds to l millisecond in the order of the low to the high tone pitch frequency of keys depressed.

When the switch 21 is thrown toward the VCO 22, then a DC voltage is impressed on the VCO 22 through any of the auxiliary switches 18-1 to l8-n. This VCO 22 is a sine wave oscillator for producing a sine wave signal having a frequency of, for example, 2 to 10 Hz according to the level of an input voltage. Where an output sine wave signal from the VCO 22 has its amplitude previously so set as to correspond to a difference between the voltage obtained through the switch 18-1 and that impressed through the switch 18-n, then an output signal from the VCO 17. will have its frequency varied at a'per second rate corresponding to the frequency of said sine wave signal. Where a key of medium pitch on the keyboard is depressed,-then the VCO 22 supplies a sine wave signal of 6 Hz to the VCO l7, and in consequence the BBD 14 receives a pulse signal whose frequency varies within the range of 40 to 100 kHz at the rate of 6 Hz'per second.

In this case, the time delay with which musical tones are generated varies at a rate defined by the compass of the musical tones produced. Namely, where the VCO 22 is made to receive a high voltage signal upon depression of highpitch keys, then the time delay varies at a quick rate for high pitch tones and a slow rate for low pitch tones. Conversely, where the VCO 22 is made to receive a low voltage upon depression of high pitch keys, then the time delay varies at a slow rate for high pitch tones and a quick rate for low pitch tones.

Such arrangement enables musical tones to be delivered with a time delay automatically varied at a rate corresponding to the pitch of keys depressed, thus attaining a versatile expressive performance which is particularly provided with a vibrato effect and a broadened variety of respective musical tones due to the time delay of the tones being freely varied.

Further, where an output signal from the tone coloring circuit 13 is conducted to a delaying device consisting of numerous elements to cause the time delay to be varied with different phases, then an ensemble effect will be more distinctly obtained to elevate the versatility of a performance. p a

This invention is also effectively applicable to a double keyboard type electronic musical instrument. FIG.

.3 is a block circuitdiagram of such type of electronic musical instrument according to another embodiment of this invention. The upper and lower keyboard devices 12a and 12b selectively deliver tone signals corresponding to the keys depressed from the tone generators 11. The tone signalsproduced are conducted to tonecoloring circuits 13a and 13b, where they are converted into musical tone signals. These musical tone signals are delivered to BBDs 14a and 14b. in this case, the upper keyboard device 12a includes a compass ranging, for example, from C3 (131 Hz) to C7 (2,093 Hz) and the lower keyboard device 12b a compass extending, for example, from C2 (65 Hz) to C6 (1,047 Hz). The upper and lower keyboard devices 12a and 12b are provided, as in FIG. 2, with control voltage generators 18a and 18b, respectively which have the same circuit arrangement as shown in FIG. 2. However, the control voltage generator 18a connected to the upper keyboard 12a has its switch 21 impressed with a rate. On the other hand, the control voltage generator 18b connected to the lower keyboard device 12b has the polarity of DC voltage relative to the potentiometer 20b reversed, as indicated in FIG. 4, from what is observed in FIG. 2. In the lower keyboard device 12b,

' therefore, the switch 21 is supplied with a low DC.

voltage when a'high pitch key is depressed, causing the time delay with which musical tone signals are delivered from the BBD 14b to be lengthened or the time delay to be varied at a slow rate.

An electronic musical instrument arranged as described above can display a very versatile performance, because musical tone signals derived from the corresponding keys on the upper and lower keyboard devices 12a and 12b have different phases or these phases vary at different rates. Since the phases also vary with the compasses represented by the keys depressed, the tone generator circuit 11, though of a frequency division type with a single generator, still attains the same effect as is possible with a multi-generator type, offering a better ensemble effect capable of providing a broadened variety of respective musical tones.

The foregoing description relates to the case where the upper and lower keyboard devices 12a and 12b were designed to cause musical tone signals to be delivered therefrom with varying time delays. However, even if only one of said keyboard devices 124 and 12b is designed to be subjected to such time delays, a desired effect will be fully obtained.

The embodiment of this invention shown in FIGS. 3 and4 enables corresponding musical tones produced on the upper and lower keyboard devices 120 and 12b to be clearly distinguished from each other, thereby attaining a versatile performance.

What is claimed is:

1. An electronic musical instrument comprising:

tone signal generators producing tone signals;

a keyboard device connected to said tone generators and selectively delivering keyed tone signals corresponding to the keys of the keyboard device which are depressed; I

means for converting said keyed tone signals from the keyboard device into musical tone signals having prescribed tone colors;

a signal delaying device coupled to an output of said converting means for delaying said musical tone signals received from said converting means;

a control voltage generator associated with said keyboard device and generating a control voltage representative of which of said keys of said keyboard device are depressed;

a transfer clock pulse generator of the voltage controlled type coupled to the output of said control voltage generator, said clock pulse generator generating transfer clock pulses the frequency of which is a function of the control voltage generated by said control voltage generator; and

means coupling the output of said transfer clock pulse generator to said signal delaying device, the delay time of said signal delaying device being determined by the frequency of said transfer clock pulses supplied thereto.

2. An electronic musical instrument according to claim 1 which further includes a second voltage controlled oscillator supplied with said control voltage, the output of said second voltage controlled oscillator being coupled to said transfer clock pulse generator to vary the frequency of said transfer clock pulses.

3. An electronic musical instrument according to claim 1 wherein said signal delaying device comprises a bucket brigade device.

4. An electronic musical instrument comprising:

tone generators producing tone signals;

first and second keyboard devices for selectively delivering keyed tone signals corresponding to the keys which are depressed;

means for converting keyed output tone signals from said first and second keyboard devices into musical tone signals having prescribed tone colors;

at least one signal delaying device coupled to an output of said converting means for delaying said musical tone signals received from said converting means;

a control voltage generator associated with said keyboard devices and generating a control voltage representative of which of said keys of said keyboard devices are depressed;

a transfer clock pulse generator of the voltage controlled type coupled to the output of said control voltage generator, said transfer clock pulse generator generating transfer clock pulses the frequency of which is a function of the control voltage generated by said control voltage generator; and

means coupling the output of said transfer clock pulse generator to said signal delaying device, the

delay time of said signal delaying device being determined by the frequency of said transfer clock pulses supplied thereto.

5. An electronic musical instrument according to claim 4 wherein said first and second keyboard devices are respectively provided with:

afirst and a second control voltage generator for generating a DC. voltage having a magnitude corresponding to the keys depressed; and

first and second voltage controlled oscillators coupled to said control voltage generators, respectively;

output signals from said first and second voltage controlled oscillators being supplied to said at least one signal delaying device.

6. An electronic musical instrument according to claim 4 wherein said at least one signal device comprises a bucket brigade device.

7. An electronic musical instrument according to claim 5 wherein said at least one signal delaying device includes first and second delaying devices coupled to said converting means and being respectively coupled to said first and second voltage controlled oscillators.

8. An electronic musical instrument according to claim 7 wherein each of said signal delaying devices comprises a bucket brigade device.

9. An electronic musical instrument according to claim 4 which further includes a second voltage controlled oscillator supplied with said control voltage, the output of said second voltage controlled oscillator being coupled to said transfer clock pulse generator to vary the frequency of said transfer clock pulses.

10. An electronic musical instrument according to claim 4 wherein said first and second keyboard devices areupper and lower keyboard devices, respectively. 

1. An electronic musical instrument comprising: tone signal generators producing tone signals; a keyboard device connected to said tone generators and selectively delivering keyed tone signals corresponding to the keys of the keyboard device which are depressed; means for convErting said keyed tone signals from the keyboard device into musical tone signals having prescribed tone colors; a signal delaying device coupled to an output of said converting means for delaying said musical tone signals received from said converting means; a control voltage generator associated with said keyboard device and generating a control voltage representative of which of said keys of said keyboard device are depressed; a transfer clock pulse generator of the voltage controlled type coupled to the output of said control voltage generator, said clock pulse generator generating transfer clock pulses the frequency of which is a function of the control voltage generated by said control voltage generator; and means coupling the output of said transfer clock pulse generator to said signal delaying device, the delay time of said signal delaying device being determined by the frequency of said transfer clock pulses supplied thereto.
 2. An electronic musical instrument according to claim 1 which further includes a second voltage controlled oscillator supplied with said control voltage, the output of said second voltage controlled oscillator being coupled to said transfer clock pulse generator to vary the frequency of said transfer clock pulses.
 3. An electronic musical instrument according to claim 1 wherein said signal delaying device comprises a bucket brigade device.
 4. An electronic musical instrument comprising: tone generators producing tone signals; first and second keyboard devices for selectively delivering keyed tone signals corresponding to the keys which are depressed; means for converting keyed output tone signals from said first and second keyboard devices into musical tone signals having prescribed tone colors; at least one signal delaying device coupled to an output of said converting means for delaying said musical tone signals received from said converting means; a control voltage generator associated with said keyboard devices and generating a control voltage representative of which of said keys of said keyboard devices are depressed; a transfer clock pulse generator of the voltage controlled type coupled to the output of said control voltage generator, said transfer clock pulse generator generating transfer clock pulses the frequency of which is a function of the control voltage generated by said control voltage generator; and means coupling the output of said transfer clock pulse generator to said signal delaying device, the delay time of said signal delaying device being determined by the frequency of said transfer clock pulses supplied thereto.
 5. An electronic musical instrument according to claim 4 wherein said first and second keyboard devices are respectively provided with: a first and a second control voltage generator for generating a D.C. voltage having a magnitude corresponding to the keys depressed; and first and second voltage controlled oscillators coupled to said control voltage generators, respectively; output signals from said first and second voltage controlled oscillators being supplied to said at least one signal delaying device.
 6. An electronic musical instrument according to claim 4 wherein said at least one signal device comprises a bucket brigade device.
 7. An electronic musical instrument according to claim 5 wherein said at least one signal delaying device includes first and second delaying devices coupled to said converting means and being respectively coupled to said first and second voltage controlled oscillators.
 8. An electronic musical instrument according to claim 7 wherein each of said signal delaying devices comprises a bucket brigade device.
 9. An electronic musical instrument according to claim 4 which further includes a second voltage controlled oscillator supplied with said control voltage, the output of said second voltage controlled oscillator being coupled to said transfer clock pulse generator to vary the frequency oF said transfer clock pulses.
 10. An electronic musical instrument according to claim 4 wherein said first and second keyboard devices are upper and lower keyboard devices, respectively. 